Motorcycle Repair: dr 200, valve timing, needle valve

Question
Hi, I have sealed the boot completly on the bike so the is no possible way for air to come in before the carb, but the engine is still not running right. It will only peak out at like 1/4 throttle then floods, it idles good most of the time but still its not very consistent. The carbs been cleaned several times. What else could it be??

The machine has been recently rebuilt by another person and I had an idea that the timing adjustment(Which has two lines up top) could be out 180 degrees to the flywheel because it doesnt say top or bottom, if you know what Im trying to say...

Answer
If the valve timing is off that would certainly cause
problems. Even though you checked the carb,
if the main jet is plugged, it won't run right.
You may need to physically clean the jet.
If it is flooding (too much gas) then the float needle
valve is leaking in the carb or the float level
is too high. Can the guy that rebuilt the engine
double-check the valve timing for you?
You can check the compression, that may be a good
indication of bad valve timing or possibly
a bent valve. A plugged exhaust can cause bogging.
Have you checked to see if the fuel is getting to the carb
from the tank?